OBJECTIVES: l. To improve the assay of the specific glycoprotein induced by application of retinoic acid to skin tunors 2. to correlate the induction of this glycoprotein with mucous metaplasia and with tumor regression. GOALS SET FOR CURRENT YEAR: 1. To relate the induction of the specific glycoprotein in mouse skin and mouse skin tumors to the development and regression of these tumors, followed biochemically and histologically. 2. To elucidate the properties, sugar composition and structure of the induced glycoprotein. 3. To study the relationship of the induced glycoprotein to the enzyme, ornithine decarboxylase, induced by promoter.